The Corporate events page lists mergers and acquisitions, capital raisings, buy-backs, material agreements, management changes, delistings and similar events.
US companies
US events come from the SEC filing index. Each one is classified from the form type and, for 8-K reports, the item numbers. For example, a Form 425 or S-4 means a business combination is under way, a merger proxy means shareholders will vote, 8-K item 2.01 reports a completed acquisition and item 1.02 a terminated agreement. Each event shows which form or item it was classified from.
ASX companies
ASX events come from ASX's announcements feed, using the announcement type and headline. ASX's price-sensitive flag is shown as is.
Deal terms
The filing index doesn't say who is buying, the price or how it will be paid, so those terms show as "not stated in the source" unless the form itself establishes them. Open the original document for the terms. Coverage starts from when collection began, and an empty list doesn't mean nothing happened.